Liz offers the Doctor a spare ticket to a conference in Paris on psi
powers and psychic phenomenon; Professor Brockhurst, who was originally to
attend the conference, recently choked to death in a restaurant. Their
plane's engine unexpectedly explodes, but a telepathic young woman on the
flight is able to keep it in flight. The Doctor keeps her mind focussed
on her task until the plane lands, although this costs the young woman her
life. Liz recognizes her as a student of Professor Hardin, Brockhurst's
rival at Cambridge, but when they return to Cambridge to confront Hardin he
drives them out of his office without explaining his work. Suspecting that
Hardin is responsible for Brockhurst's death and is conducting unethical
experiments upon student volunteers, the Doctor calls in the Brigadier and
with Liz's help organises a mass protest against Hardin. Hardin has been
conducting surgery on his students to release their psychic potential, and
apparently has been using a psychokinetic student to kill his rivals; the
plane was brought down to prevent the young woman from revealing Hardin's
unethical experiments to the conference. The Doctor realizes that Hardin
is trying to create an army of psychic assassins to sell to the highest
bidder, but when he confronts Hardin he discovers that Hardin has also
conducted experiments upon himself. Having killed his unstable assassin,
Hardin attempts to crush the Doctor's lungs within his body, but at that
moment the Brigadier enters and shoots him dead.

The Doctor and Jo are called away from a scientific conference by an
urgent message from the Brigadier, and arrive at a UNIT training area to
find Colonel Ashe waiting for them. Ashe claims that the Brigadier has been
unavoidably detained and that they must meet elsewhere, but as they approach
Ashe's helicopter Ashe erroneously identifies a target Auton as an Ogron --
revealing that he isn't a UNIT soldier after all. The Doctor gets away but
Ashe threatens to kill Jo if the Doctor doesn't show himself; Ashe is in
fact a Soviet officer who has come to take the Doctor to the other side of
the Iron Curtain to work for them. The Brigadier arrives just in time to
rescue the Doctor and Jo, or so he thinks until the Doctor reveals that
while Ashe was holding Jo prisoner, the Doctor was filling the gas tank
of Ashe's helicopter with sugar.

Time-Placement: Prior to The Wages of Sin since the Doctor has not been to Russia for centuries.
It's probably a difficult time for UNIT since they are closing base 43, last seen in the The Sea Devils. As the short story
Where the Heart Is references cuts made to UNIT budget by the British government, we place this story just after.

The Third Doctor visits UNIT's detention centre at Aylesbury Grange,
where the Master is being held prior to his trial. The Master claims that
he has reformed and wishes to help repair the damage he has caused over the
years, but much as the Doctor would like to believe him, he can't. The
Master then reveals that he's already escaped and disguised himself as his
own guard; the Doctor has been speaking to a holographic illusion. But as
the Master departs he is confronted outside the cell block by UNIT troops
and by the real Doctor. Suspecting the Master's intentions, the Doctor had
sent in a hologram to speak with the Master.

Time-Placement: Prior to The Sea Devils since the Master is still detained at Aylesbury Grange.
We speculate that his attempt to escape would lead to his transfer to the facility seen
in the The Sea Devils shortly after.